I like the idea of using the holographic combat troops. Even without the advanced holoemitter from Voyager (now that it has returned), using holoemitters to produce specialized units to either defend a ship from boarding or free up/defend a installation would work.
Imagine if you took it a step further and instead of a holographic security guard with a phaser you created hordes of armoured spider-things with built-in weaponry, capable of walking on any surface, even ceilings.